專案背景
今天心血來潮,以前不常寫東西,接觸angular以來,覺得有必要分享一些新的體會了,於是來到了這裡。
- 管道Pipe可以將資料作為輸入,然後按照規則將其轉換並輸出。
建立專案
ng new meepo-underscore
cd meepo-underscore
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建立module和初始化pipe
ng g m meepo-underscore
ng g pipe map
ng g pipe flatten
ng g pipe invert
ng g pipe range
ng g pipe sample
ng g pipe shuffle
ng g pipe values
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分析需求及實現
- map 結構轉陣列
meepo-underscore/map.pipe.ts
import { Pipe, PipeTransform } from "@angular/core";
import * as _ from "underscore";
@Pipe({
name: "map"
})
export class MapPipe implements PipeTransform {
transform(value: any, args?: any): any {
let re = _.map(value, (item, key) => {
return { item: item, key: key };
});
return re;
}
}
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- 使用
let obj = {
name: "bob",
school: "school",
address: "xueyuan"
}
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<div *ngFor="let item of obj | map">
{{item.key}}:{{item.item}}
</div>
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- flatten 接收一個Array,無論這個Array裡面巢狀了多少個Array,flatten()最後都把它們變成一個一維陣列
meepo-underscore/flatten.pipe.ts
import { Pipe, PipeTransform } from "@angular/core";
import * as _ from "underscore";
@Pipe({
name: "flatten"
})
export class FlattenPipe implements PipeTransform {
transform(value: any, args?: any): any {
return _.flatten(value);
}
}
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- 使用
<div *ngFor="let item of [[1],[2],[3,4,5]] | flatten">
{{item.key}}:{{item.item}}
</div>
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- invert 把object的每個key-value來個交換,key變成value,value變成key
import { Pipe, PipeTransform } from '@angular/core';
import * as _ from "underscore";
@Pipe({
name: 'invert'
})
export class InvertPipe implements PipeTransform {
transform(value: any, args?: any): any {
return _.invert(value);
}
}
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- 使用
<div *ngFor="let item of [{key1:'item1'},{key2:'item2'}] | invert | map">
{{item.key}}:{{item.item}}
</div>
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- range 區間陣列
import { Pipe, PipeTransform } from "@angular/core";
import * as _ from "underscore";
@Pipe({
name: "range"
})
export class RangePipe implements PipeTransform {
transform(value: any, args?: any): any {
return _.range(value, args);
}
}
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- 使用
<div *ngFor="let item of 0 | range:10">
{{item}}
</div>
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- sample 隨機選擇一個或多個元素:
import { Pipe, PipeTransform } from "@angular/core";
import * as _ from "underscore";
@Pipe({
name: "sample"
})
export class SamplePipe implements PipeTransform {
transform(value: any, args?: any): any {
let item = _.sample(value, args);
return item;
}
}
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- 使用
<h2 class="title">_.sample</h2>
<div *ngFor="let item of obj | map | sample:4">
{{item.item}}
</div>
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- shuffle 用洗牌演算法隨機打亂一個集合
import { Pipe, PipeTransform } from '@angular/core';
import * as _ from "underscore";
@Pipe({
name: 'shuffle'
})
export class ShufflePipe implements PipeTransform {
transform(value: any, args?: any): any {
return _.shuffle(value)
}
}
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<h2 class="title">_.shuffle</h2>
<div *ngFor="let item of obj | map | shuffle">
{{item.key}}-{{item.item}}
</div>
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- values 物件值遍歷
import { Pipe, PipeTransform } from '@angular/core';
import * as _ from "underscore";
@Pipe({
name: 'values'
})
export class ValuesPipe implements PipeTransform {
transform(value: any, args?: any): any {
return _.values(value);
}
}
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釋出準備
新建package.json
{
"name": "meepo-underscore",
"version": "2.0.2",
"repository": "https://github.com/meepobrother/meepo-underscore.git",
"author": "imeepos <1037483576@qq.com>",
"license": "MIT",
"private": false,
"scripts": {
"git": "git add . && git commit -m 'push to save' && git push origin master"
},
"peerDependencies": {
"@angular/core": "*",
"@angular/common": "*",
"rxjs": "*",
"underscore": "*"
},
"ngPackage": {
"$schema": "./node_modules/ng-packagr/ng-package.schema.json",
"dest": "../../../meepo/underscore",
"workingDirectory": "./.ng_build",
"lib": {
"entryFile": "./public_api.ts"
}
}
}
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匯出模組
import { NgModule } from "@angular/core";
import { CommonModule } from "@angular/common";
import { MapPipe } from "./map.pipe";
import { ShufflePipe } from "./shuffle.pipe";
import { SamplePipe } from "./sample.pipe";
import { RangePipe } from "./range.pipe";
import { FlattenPipe } from "./flatten.pipe";
import { ValuesPipe } from "./values.pipe";
import { InvertPipe } from "./invert.pipe";
export const PIPES = [
MapPipe,
ShufflePipe,
SamplePipe,
RangePipe,
FlattenPipe,
ValuesPipe,
InvertPipe
];
@NgModule({
imports: [CommonModule],
declarations: [...PIPES],
exports: [...PIPES]
})
export class UnderscoreModule {}
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釋出到npm
ng-packagr -p ./src/app/shared/underscore/package.json
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使用安裝
yarn add meepo-underscore
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import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';
import { RouterModule } from '@angular/router';
import { UnderscoreModule } from 'meepo-underscore';
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
RouterModule.forRoot([]),
UnderscoreModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
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總結
本文介紹了 Angular 自定義管道pipe的方法,併發布到npm, 方便使用及管理。